JP2000227009A - Valve lifter and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a valve lifter, in which the strength of an abutting plate pushed/pressed from the cam side is enhanced, and the method for manufacturing it. SOLUTION: A valve lifter main body 10 is provided with a cylindrical wall 11 and an abutting plate 12 capable of abutting a valve stem 16. The cylindrical wall 11 is provided with a projected part 22a, which is formed by folding a plate piece, and a supporting part 20. The projected part 22a is placed almost normal to the horizontal surface of a shim 15, while the supporting part 20 is placed almost parallel to the horizontal surface of the shim 15. A corner part 11a located at a boundary between the abutting plate 12 and the projected part 22a is formed into a recessed, scooped shape. The supporting part 20 is protrusively formed on the inner peripheral surface side of the cylindrical wall 11, while a supporting surface 20a of the supporting part 20 abuts on the abutting plate 12 while supporting the abutting plate 12. By supporting the abutting plate 12 using the supporting part 20, the strength of the abutting plate 12 can be enhanced against the pushing/pressing pressure acting from the cam (17) side in the direction marked by an arrow 50.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a valve lifter for opening and closing a valve provided on a cylinder head in accordance with rotation of a camshaft in an engine of an automobile or the like, and a method of manufacturing the same.

[0002]

2. Description of the Related Art A bottomed cylindrical valve lifter (or "tappet") provided in a valve train of an engine of an automobile or the like.
Also called. ), The cam contact portion is pressed with the rotation of the cam of the camshaft linked to the crankshaft of the engine,
The valve stem is pressed by the valve stem contact portion to move them up and down. A valve lifter of this type and a manufacturing method thereof are described in JP-A-55-40269. This publication describes a technique for manufacturing a valve lifter by using press forming which is economically advantageous as compared with a case where manufacturing is performed by cold forging. A conventional valve lifter described in this publication will be described with reference to a longitudinal sectional view of FIG.

As shown in FIG. 12, a valve lifter main body 3 is provided.
Numeral 0 is formed into a bottomed cylindrical shape by press molding (drawing), and has a contact plate 32 on the inner peripheral surface of the cylindrical wall 31. The protruding portion 31a standing on the bottom of the bottomed cylindrical shape is formed by folding a plate piece by flat striking.
1b. A valve stem 36 is inserted into a space 33 formed by partitioning the cylindrical wall 31 by a contact plate 32, and the valve stem 36 contacts a valve stem contact surface 32 a of the contact plate 32. Further, a reinforcing shim 35 which contacts the cam 37 is disposed in a space 34 formed by partitioning the cylindrical wall 31 by the contact plate 32, and the shim 35 is a shim contact surface 32 b of the contact plate 32. Abut. Also, the contact plate 32
A projection 38 for increasing the strength of the contact plate 32 is provided at a central position of the valve stem 32. The projection 38 is formed with a valve stem contact surface 32a.

[0004]

During operation of the engine, the shim 35 is periodically pressed in the direction of the arrow 51 in FIG. 12 with the rotation of the cam 37, and the contact plate 32 is moved through the shim 35. 12 is pressed in the direction of arrow 51 in FIG.
As a result, the valve stem 36 moves in the direction of the arrow 51. The conventional valve lifter shown in FIG. 12 receives this pressing force by the contact plate 32. However, when a pressing force in the direction of arrow 51 in FIG. 12 acts on the contact plate 32, stress concentrates near the bent portion of the plate piece formed between the protrusion 31 a and the contact plate 32. Therefore, the valve lifter main body 30 having the configuration shown in FIG. 12 has a problem in the strength of the contact plate 32 pressed from the cam side.

[0005] An object of the present invention is to provide a valve lifter in which the strength of a contact plate pressed from the cam side is improved and a method of manufacturing the same.

[0006]

In order to solve the above-mentioned problems, a valve lifter according to the present invention is configured as described in claim 1. According to the valve lifter of the first aspect, when the contact plate is pressed by the cam, the contact plate can be supported by the support portion. Therefore, the strength of the contact plate against the pressure from the cam can be improved, and a high-strength valve lifter can be realized.

Further, the valve lifter of the present invention is characterized in that
Is configured as described in. When the valve lifter according to the second aspect is used, a high-strength valve lifter can be realized, and the weight can be reduced because the valve lifter is formed by press molding.

Further, a method of manufacturing a valve lifter according to the present invention is configured as described in claim 3. Claim 3
If the valve lifter manufacturing method described in (1) is used, the valve lifter can be formed by press molding, so that the valve lifter can be processed quickly and with high precision.
For example, when manufacturing a valve lifter by cold forging, mechanical cutting is necessary after forging, but press cutting does not require mechanical cutting due to high processing accuracy. Therefore, the manufacturing cost of the valve lifter can be reduced as compared with the cold forging.

Further, the valve lifter of the present invention is characterized in that
Is configured as described in. When the valve lifter is pressed by the cam of the camshaft, resonance of the valve lifter occurs with this pressing. When such resonance occurs, the durability of the valve lifter may be reduced due to abrasion with a peripheral portion, or abnormal noise may be generated. When the valve lifter according to claim 4 is used, a high-strength valve lifter can be realized, and since the protrusion is provided on the inner peripheral surface side of the cylindrical wall, the rigidity of the valve lifter can be increased, and the valve lifter is pressed by the cam of the camshaft. In this case, the occurrence of resonance of the valve lifter can be prevented. Also,
Since the occurrence of such resonance can be prevented, it is possible to prevent rattling of the valve lifter body and generation of abnormal noise.

[0010] A method of manufacturing a valve lifter according to the present invention is configured as described in claim 5. Claim 5
When the valve lifter described in (1) is used, the projection on the inner peripheral surface side of the cylindrical wall can be easily formed by press molding.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A valve lifter according to an embodiment of the present invention will be described based on an example. FIG. 1 is a longitudinal sectional view of a valve lifter according to an embodiment. FIG. 2 is a longitudinal sectional view of a valve lifter according to another embodiment. As shown in FIG. 1, the valve lifter according to the present embodiment includes a valve lifter body 10, a shim 15, and the like. The valve lifter body 10 has a cylindrical tube wall 11.
And a contact plate 12 capable of contacting the valve stem 16. The cylindrical wall 11 is provided with a protruding portion 22a and a support portion 20 formed by folding a plate piece. Projection 22a
Is provided substantially perpendicular to the horizontal plane of the shim 15,
The support portion 20 is provided in a direction substantially parallel to the horizontal plane of the shim 15. The cylindrical wall 11 is partitioned by a contact plate 12,
Spaces 13 and 14 are formed. The space 13 is formed into a shape into which the valve stem 16 can be inserted.
4 is formed in a shape in which the shim 15 can be installed. Further, in order to facilitate replacement of the shim 15, a notch (not shown) is provided in a part of the protrusion 22a.

The contact plate 12 has a valve stem contact surface 12 a on the valve stem 16 side, and the shim 1 which contacts the cam 17.
A shim contact surface 12b is provided on the fifth side. Also, the contact plate 1
A projection 18 for increasing the strength of the contact plate 12 is provided at a central position of the projection 2, and the projection 18 is formed with a valve stem contact surface 12a. Also, the contact plate 12
A corner 11a having a concave shape is formed at a boundary position between the projection 22a. The corner 11a is formed in an arc shape in which each of the contact plate 12 and the protrusion 22a is partially hollowed out. By forming the corner 11a in such a shape, the corner of the shim 15 can be prevented from contacting the corner 11a, and the stress received from the shim 15 side is less likely to concentrate on the corner 11a. In addition, if heat treatment is performed after press molding, slight distortion occurs, so that it is necessary to perform a grinding process. Particularly, a portion of the abutment plate 12 and the protrusion 22a where the shim 15 abuts is required to have high processing accuracy, and therefore, a grinding process is performed after the heat treatment. In the case of performing such a grinding process, if the corner portion 11a is formed, the process by the grinding tool becomes easy, and the portion of the contact plate 12 and the protrusion 22a with which the shim 15 contacts can be accurately and reliably. Grinding process can be performed.

The support portion 20 is formed in a convex shape on the inner peripheral surface side of the cylindrical wall 11, and the support surface 20 a of the support portion 20 contacts the contact plate 12 to support the contact plate 12. By supporting the contact plate 12 by the support portion 20 in this manner, the strength of the contact plate 12 can be improved with respect to the pressing in the direction of the arrow 50 in FIG.

As shown in FIG. 2, a projection 40 formed by folding a plate piece of the cylindrical wall 11 on the inner peripheral surface side of the cylindrical wall 11 is formed.
Can be provided. The protrusion 40 is provided along the inner peripheral surface at a position from the indicating portion 20 to the open end of the cylindrical wall 11. If the rigidity of the valve lifter main body 10 is low, the valve lifter main body 10 resonates when the shim 15 is pressed with the rotation of the cam 17 of the camshaft. And
Due to this resonance, wear on the peripheral portion occurs, and the durability of the valve lifter main body 10 decreases. In the present embodiment, the cylindrical wall 1
Since the protrusions 40 are provided on the first member 1, the valve lifter main body 10 having high rigidity can be realized. Therefore, the resonance of the valve lifter main body 10 can be prevented, and the durability of the valve lifter main body 10 can be improved. Further, it is possible to prevent generation of abnormal noise and rattling caused by resonance of the valve lifter main body 10. Note that the height t of the protrusion 40 can be appropriately changed as long as the height t does not abut on the valve stem 16.

Next, a method of manufacturing the valve lifter of this embodiment will be described with reference to FIGS. 3 to 11 are vertical sectional views of the valve lifter main body in each manufacturing process.
In this embodiment, a manufacturing method in which the valve lifter body is formed by “press molding” is used. In the "press forming" as referred to in the present invention, "bending" for bending a workpiece such as a plate piece, or pressing the workpiece into a predetermined mold,
"Drawing" and "upsetting" to crush and form
In addition, it also includes “trimming processing” for cutting and shaping the end of the workpiece, and shaping work performed to increase the processing accuracy of the workpiece after performing the above processing.

First, a metal material having a predetermined thickness (in this embodiment, a thickness of 1 mm) is drawn in the order of FIGS. 3 to 5 to form a bottomed cylindrical shape. In the first step shown in FIG. 3, the cup-shaped body 21A is formed by drawing. The cup-shaped body 21A includes a bottom 21a and a side plate 21b, and has an inner diameter L.
1, formed at a height H1. A substantially arc-shaped edge portion 21c extending outward is formed on the end face of the side plate 21b on the opening side.

Next, in a second step shown in FIG. 4, further drawing is performed to obtain an inner diameter L2 (L1> L2) and a height H2.
A cup-shaped body 21B (H1 <H2) is formed. Here, the cup-shaped body 21B is formed by being reduced in the radial direction and stretched in the height direction.

Next, in a third step shown in FIG. 5, a further drawing process is performed to form a side plate 21b having an inner diameter L2 and a side plate 21b.
A cup-shaped body 21C having a hemispherical hemispherical portion 22 having a diameter L3 slightly smaller than the inner diameter L2 of the cup is formed. At this time, the step 2 is located at the boundary position between the side plate 21b and the hemisphere 22.
1d is formed in an inclined shape.

Next, in a fourth step shown in FIG. 6, the edge 21c of the cup-shaped body 21C and the step 21d having a substantially circular arc shape are formed.
To form a cup-shaped body 21D. Here, the substantially circular edge portion 21c and the inclined step portion 21d are both formed substantially at right angles to the side plate 21b.

Next, in a fifth step shown in FIG. 7, a part of the edge 21c of the cup-shaped body D (a part protruding outside) is cut by a trimming process to form a cylinder having substantially uniform outer and inner diameters. A cup-shaped body 21E having the wall 11 is formed. At this time, the cut surface is formed in a shape inclined toward the inner peripheral surface.

Next, in a sixth step shown in FIG. 8, a cup-shaped body 21F having projections 22a, 22c and a support portion 22b is formed on the hemispherical portion 22. The substantially U-shaped protrusion 22a is formed so as to protrude outside the cylinder wall 11, and the substantially U-shaped support portion 22b is formed so as to protrude inside the cylinder wall 11. The substantially arc-shaped protrusion 22c is formed at the center of the hemisphere 22 so as to protrude outward.

Next, in a seventh step shown in FIG. 9, the substantially U-shape of the projection 22a and the support portion 22b of the cup-shaped body 21F is bent so as to be crushed, and the slit 23
A cup-shaped body 21G having a and 23b is formed. At this time, the protruding portion 22a and the support portion 22b are formed substantially perpendicular to the axial direction of the cylindrical wall 11.

Next, in an eighth step shown in FIG. 10, the protruding portion 22a of the cup-shaped body 21G is bent in the axial direction of the cylindrical wall 11 to stand up, thereby forming the cup-shaped body 21H. The projection 22a is formed such that its outer diameter is substantially the same as the outer diameter of the cylindrical wall 11.

Next, in a ninth step shown in FIG. 11, the cup-shaped body 21H is formed by upsetting to form a cup-shaped body 21I. Here, the projection 22c is formed into the flat contact plate 12, and the projection 18 is formed at the center of the contact plate 12. Thereby, the valve stem 1
A space 13 in which the shim 15 can be installed and a space 14 in which the shim 15 can be installed are formed. In addition, the space part 14 is a shim 15
It is processed with high precision according to the shape of Also, the contact plate 1
The corner 11a at the boundary between the projection 2 and the projection 22a is formed in a concave shape by a mold member (not shown).

Finally, the workpiece is entirely stamped with a mold member (not shown) to correct the distortion, displacement, and the like generated in the above-mentioned machining process. In addition, the end surface of the cylindrical wall 11 on the opening side is chamfered into a shape in which a cut surface is inclined in an outward direction. In addition, a cutting process is performed, and a cutout is formed in a part of the protrusion 22a to facilitate replacement of the shim 15. By such a forming process, dimensional accuracy of the valve lifter main body 10 can be obtained, and a highly accurate valve lifter can be realized.

Thereafter, the valve lifter 10 is finished by heat treatment (carburizing and quenching) or polishing of each part to form the valve lifter 10 as shown in FIG. In addition, any of the steps described above can be performed by progressive press molding.

Also, in a step different from the progressive press forming as described above, after the ninth step shown in FIG.
The protrusion 40 can be formed by folding back one plate piece by press molding.

According to the valve lifter of the present embodiment configured as described above, since the supporting portion 20 for supporting the contact plate 12 is formed, the valve lifter can be pressed from the cam 17 side in the direction of arrow 50 in FIG. Thus, the strength of the contact plate 12 can be improved. Further, since the valve lifter main body 10 can be manufactured by press molding, the weight of the valve lifter can be reduced. Furthermore, for example, the manufacturing cost of a mold member is lower than that in the case of manufacturing using cold forging, the processing speed is high, and the mechanical cutting work required after the cold forging process is omitted. Can be. Therefore, the valve lifter main body 10 having high processing accuracy and low manufacturing cost can be realized. In addition, corner 11
Since a is provided, a portion of the contact plate 12 and the protruding portion 22a with which the shim 15 contacts can be accurately and reliably ground. Further, since the protrusion 40 is provided, the rigidity of the valve lifter main body 10 can be increased, and resonance of the valve lifter main body 10 and generation of abnormal noise due to the resonance can be prevented. Further, according to the valve lifter manufacturing method of the present embodiment, since any of the steps can be performed by press molding, it is possible to manufacture the valve lifter main body 10 with high processing accuracy at a low cost as compared with, for example, cold forging. Can be. In addition, since a step of finally embossing the valve lifter main body 10 is provided, it is possible to correct distortion, displacement, and the like generated during the processing in the middle.
Processing accuracy can be improved. Further, the projection 40 of the cylindrical wall 11 can be easily formed by press molding.

It should be noted that the present invention is not limited to only the above-described embodiment, and various applications and modifications are conceivable. In the above embodiment, the valve lifter main body 1 is formed by press molding.
Although the first to ninth steps of manufacturing 0 have been described, the order of processing, the number of steps, and the like can be changed as necessary. In addition, after the ninth step, a step of forming the projection 40 by folding back the plate piece of the cylindrical wall 11 by press molding is provided, but the step may be performed before the ninth step. Also,
Although the support portion 20 and the protruding portion 22a are formed in a shape obtained by bending the plate piece once, the number of times of folding, the shape and the like can be changed. Further, the support portion 20 or the protruding portion 22a can be formed in a convex shape without folding by upsetting. Further, although the support portion 20 is provided on the valve lifter formed by press molding, the support portion 20 may be provided on a valve lifter formed by cold forging or the like. Further, although the cylindrical wall 11 is formed in a cylindrical shape, the cross-sectional shape of the cylindrical wall 11 can be appropriately changed. In addition, the protrusion 40 is provided along the inner peripheral surface at a position from the indicating portion 20 to the open end of the cylindrical wall 11, but the position of the protrusion 40 is not limited as long as it is within this range. For example, it can be provided at the open end of the cylindrical wall 11. Further, the projection 40 is formed by folding a plate piece of the cylindrical wall 11, but the shape of the projection 40 is not limited to this. For example, the open end of the cylindrical wall 11 may be bent inward at a right angle to form a substantially L-shape. Further, the projection 40 is provided on the cylindrical wall 11 of the valve lifter main body 10, but the projection 40 may be omitted.

[0030]

As described above, by using the valve lifter according to the first aspect, a valve lifter having high strength can be realized. Further, when the valve lifter according to the second aspect is used, a high-strength valve lifter can be realized, and further, the weight can be reduced. Further, by using the method of manufacturing a valve lifter according to the third aspect, the valve lifter can be processed quickly and accurately. Therefore, the manufacturing cost can be reduced as compared with, for example, cold forging. Further, the use of the valve lifter according to claim 4 can prevent occurrence of resonance of the valve lifter. Further, if the method for manufacturing a valve lifter according to claim 5 is used, the projection can be easily formed.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a valve lifter according to an embodiment of the present invention.

FIG. 2 is a longitudinal sectional view of a valve lifter according to another embodiment of the present invention.

FIG. 3 is a longitudinal sectional view of a valve lifter main body showing a manufacturing process.

FIG. 4 is a longitudinal sectional view of the valve lifter main body showing a manufacturing process.

FIG. 5 is a longitudinal sectional view of a valve lifter main body showing a manufacturing process.

FIG. 6 is a longitudinal sectional view of the valve lifter main body showing a manufacturing process.

FIG. 7 is a longitudinal sectional view of the valve lifter main body showing a manufacturing process.

FIG. 8 is a longitudinal sectional view of the valve lifter main body showing a manufacturing process.

FIG. 9 is a longitudinal sectional view of the valve lifter main body showing a manufacturing process.

FIG. 10 is a longitudinal sectional view of the valve lifter main body showing a manufacturing process.

FIG. 11 is a longitudinal sectional view of the valve lifter main body showing a manufacturing process.

FIG. 12 is a longitudinal sectional view of a conventional type valve lifter.

[Explanation of symbols]

 10, 30 ... valve lifter main body 11, 31 ... cylindrical wall 11a ... corner portion 12, 32 ... contact plate 15, 35 ... shim 18, 38 ... projection 20 ... support portion 22a, 31a, 40 ... projection

Claims (5)

[Claims] 1. A cylindrical wall, a contact plate provided on the cylindrical wall, one surface of which is pressed, and a support portion provided on the other surface side of the contact plate for supporting the contact plate. A valve lifter provided with. 2. The valve lifter according to claim 1, wherein the contact plate and the support portion are formed by press molding. 3. A step of forming a plate piece into a bottomed cylindrical shape by drawing, and forming a projection on an outer peripheral surface side of the bottomed cylindrical bottom plate, and forming an inner peripheral surface of the bottomed cylindrical shape. Forming a convex supporting portion for supporting the bottom plate on the side; bending the protrusion in the axial direction of the bottomed cylindrical tube wall; and setting up the bottom plate by upsetting. And forming a concave corner at the boundary between the protrusion and the contact plate. 4. The valve lifter according to claim 1, further comprising a protrusion formed on the inner peripheral surface side of the cylindrical wall by press molding. 5. The method for manufacturing a valve lifter according to claim 3, further comprising a step of forming a projection on the inner peripheral surface side of the cylindrical wall by press molding.